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Messerschmitt Kreisflügel J 1253


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Feb 19, 2009
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Is this possibly an example of a "Flat Plate" model used for the wind-tunnel testing of new aerofoil profiles?... as opposed to an "infinite Aspect-Ratio" model (extending to the entire width of the wind-tunnel) or a "free model" - suspended within the wind-tunnel? Are these distinctions useful to the followers of this Forum?
Sorry if i have these distinctions wrong, but i'm working from memory from a Long time ago; the closest to a decent Ref. is:

Martin Symons (1975, Reprint, 1985)
Model Aircraft Aerodynamics
Argus Books, England
[ISBN 0-85242-441-8]

(Which contains data obtained from the Gottingen Windtunnels)

The book i got the distinctions of "flat plate", "Infinite" and "Free" from was one about Wind-Tunnels that i borrowed from the library years ago; which, unfortunately, i have forgotten the Title, Author and everything
Sorry, rambling at the minute...


Pardon me; i should clarify what i was trying to say above:

The book upon wind-tunnels i mentioned above informed me of a point [which is probably obvious to most of the members of this Forum; but wasn't to me :-[ at the time], ie: a Windtunnel is a Scientific Instrument -
hence, certain [almost] standardized methodologies are employed in the use of windtunnels.

Because a windtunnel is, inherently, an enclosed space, the (measured) data obtained from a model can differ quite markedly from testing a prototype in "free air" - because this affects the Reynold's Number (Re or Re.No) - the measure of the turbulence of a fluid flow around a moving body. In order to obtain more reliable data from a windtunnel - when testing a new aerofoil profile - several different forms of the new profile are tested; essentially the "infinite" and "Free" versions of the profile. Given the proximity of the sides of the windtunnel to the tips of the windtunnel model, the data can be profoundly affected (by altering the measured Re.No), which is the reason for building several different planforms for a given aerofoil profile. By testing several different planforms of a given profile, more accurate predictions can be made about how this profile will perform in "free air".
(Note that "infinite (aspect-ratio)" models yield more "mathematically Perfect" data than "free" models - amd may be used to correct predictions).

[Note: "Flat Plates" are more usually employed to "calibrate" new windtunnels - measuring how the windtunnel itself affects Re.No's within its interior, in turn, using that data to adjust data from model tests]

i suspect that this is one of a "family" of windtunnel models for a "new" aerofoil ;)
That is to say that i don't believe that it was, strictly, a design for a new aircraft; per se


[Which i'm thinking of editing... the Wiki account is a little bit inadequate ::) ]

hope the rewrite is of more help

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